I think that calling Southwest a low cost carrier is a misnomer. At least WRT what they pay their pilots.
12 yr. 737 captain:
SWA $190 per hour
Delta $173
Cont. $163
Amer. $158
5 yr. 737 first officer:
SWA $114
Delta $105
Cont. $91
Amer. $93
Those are some Legacy straight pay pilot costs